


Work It Out

by The_Littlest_Raindrop



Category: Shingeki no Kyojin | Attack on Titan
Genre: Biting, Dirty Talk, F/M, Hair Pulling, Licking, Praise Kink, Sass, Scratching, Slight Battle For Dominance, Workout
Language: English
Status: Completed
Published: 2020-02-02
Updated: 2020-02-02
Packaged: 2021-02-28 04:20:19
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,984
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22517632
Author URL: https://archiveofourown.org/users/The_Littlest_Raindrop/pseuds/The_Littlest_Raindrop
Summary: Having worked under Erwin when he was just a Squad Leader, you’re used to following his instructions. When he instructed you to help him with his workouts, you were happy to oblige.So when he decides he wants to train you, you take him up on the offer. After all, who wouldn’t want a chance to work up a sweat with Erwin?Turns out there are many ways to work up a sweat.
Relationships: Erwin Smith/Reader
Comments: 3
Kudos: 146





	Work It Out

**Author's Note:**

> A small gift for a personal friend of mine. Hope you enjoy ;)

Life in the Scout Regiment has not been what you’d expected.

In all fairness, you had expected to die soon after joining them. You’ve always been fully aware of just how high the mortality rate of your chosen military branch is, but that wasn’t enough to stop you from making the choice to give your heart for the sake of humanity.

Over the years, you’ve met many that share that conviction. While many of them have given their lives for that belief, there is still one friend that remains a constant; Erwin Smith, commander of the Survey Corps.

Of course, he wasn’t always in charge. When you’d joined the scouts, he was just a squad leader, though his ambitions shone bright even then. Having been assigned to his squad, the two of you had been forced to work closely with each other, and had managed to strike up a friendship. As your squad leader, you always counted on him to make the right decisions; he always counted on you to have his back.

Little has changed, even if he is the commander now.

His trust in you runs so deep that he has assigned you with a task few would be brave enough to accept;

When Erwin works out, you act as his motivator.

After all, who better to motive him than his friend of several years now? If there’s one thing you know, it’s what makes Erwin tick, and you use that to your full advantage.

Why then is it you currently hold two small weights, waiting for Erwin to position you? 

The answer is simple enough; after indulging him for so long by being his personal motivator, Erwin has offered to train you for a change. 

You have to admit that this is an exciting prospect. There are plenty of soldiers that would kill to have Erwin train them like this, and you’re not going to waste this opportunity!

Your thoughts suddenly focus in on Erwin, who has stripped down to just his shirt and trousers, his ODM equipment too likely to get tangled in weights to be worth keeping on. ‘Are you ready for this? I don’t intend to show you any mercy just because we’re friends. If anything, that makes me want to work you harder.’ His voice dips a couple octaves at the end of his sentence in casual flirtatiousness, something that’s become quite common between the two of you over the years.

You look at him with a confident smirk on your face. ‘You can work me as hard as you want, Erwin. You know I can take it.’ You’re dressed in a similar way to Erwin, although you’ve ditched your shirt too so you can work out in your vest; you’re going to get far too hot for layers. 

Erwin chuckles, a noise that always makes your stomach flutter. ‘I’ll remind you of that when you’re sore and exhausted. For now, keep your arms out and your back straight. I think we’ll start with squats.’ Damn, he really is trying to wear you out if he’s starting like that!

One small thing. ‘Shouldn’t I stretch first? I don’t want to pull anything.’ Come to think of it, Erwin never stretches either; that’s pretty bad form really.

Erwin smirks. ‘What, training isn’t enough of a warm up for you? Should I ask Mike to start drilling you harder?’ After Erwin’s promotion, Mike has personally requested you for his squad, a request you were happy to accept; until Levi came along, Mike was the strongest solider here, and being asked to work with him a great honour.

You call Erwin’s bluff, sticking your chest out proudly. ‘What can I say? Nobody can drill me quite like you can. How many squats do you want from me?’ You get the feeling you’re about to pay for your confidence…

Erwin smirks. ‘We’ll go for forty. I wouldn’t want to break you this early on.’ Forty huh? You can do that.

As you get into position, Erwin moves behind you, inspecting your posture. ‘You’re slouching. Keep your back straight.’ You straighten your spine the best you can with the weights in your hands, but that’s not good enough for Erwin: with one hand on your back and the other just below your breasts, he moves you into position. ‘Stick your arms out in front of you.’ You do so, trying to keep your posture.

When Erwin lets go, you somehow manage to stay in the same position. ‘Good girl, that’s it. Now squat for me.’ You have to fight off a blush; Erwin has never called you a ‘good girl’ before, but you’d be lying if you said that you hated it.

You try not to focus on that as you do your first squat, as painless as you’d expected the first to be; it just shows you’re in good shape. 

When you get back up, Erwin is smirking. ‘That’s one. I want thirty nine more just like it, and then we’ll move on to something a little better.’ You want to ask what happens if you don’t deliver, but you’re not sure you’d like the answer.

So as you squat again, you look Erwin in the eyes, trying to show that you’re more than up for this.

Thinking back, your relationship has always been like this. You’ve always been pushing each other, right from day one. Erwin saw your potential the first time he met you, and he’s not afraid to break you if it means getting the best results. In return, you’ve always pushed Erwin to move forward with his goals. The few times you’ve caught him deep in self-doubt, you’ve been the one to snap him out of it. With all this pushing each other, it’s hardly a surprise that you sometimes swear you can feel the spark of something between you, threatening to burn into something different if given the right kindling. Erwin seems content to ignore it, not wanting any kind of relationship to jeopardise his career. Perhaps he doesn’t even feel it. But you do, and as you stare into Erwin’s fierce eyes, you wonder if it would truly be a bad thing to give the spark something to ignite.

Before you know it, you’ve made it to forty squats, a thin sheen of sweat coating your body. Removing your shirt was a smart move…

Erwin crosses his arms, staring down at you. ‘You did good work. Do you still want more?’ Words of praise don’t often fall from Erwin’s lips, which makes you wonder why he’s being so generous today.

It’s not like it really matters, so you throw the weights to the floor, putting your hands on your hips. ‘You’ll need to give me something way harder than that if you want me to call it quits.’ You shouldn’t be baiting him like this, but you can’t help it; he pushes, you push back. That’s how it goes.

Erwin coughs. ‘Alright then. More weights it is. Come with me.’ Oh, this can only mean one thing; time for the bench.

Having only limited funds to spend on his hobby, Erwin has had to make so with a lot of secondhand equipment; the bench in question is a heavily worn thing, the padding barely there in a lot of places. While that might not bother Erwin, you’ve always had a rather sensitive spine; you’re not looking forward to this. 

As you shuffle into position, Erwin looms over you, making sure the weights are attached the metal pole properly. As he does this, you suddenly become aware of two things; Erwin’s crotch is mere centimetres from your face, and his trousers leave very little to the imagination.

From what you can see, Erwin was not left wanting in that particular department; while you can’t be sure just how long his dick will be when erect, the thickness you can see does nothing to soothe your earlier ache.

You try your best to ignore the little voice in your head urging you to touch him, or rub your face against him. It would be so wrong. He’s not just your commander, he’s your friend, and he’s training you out of the goodness of his…

His cock starts twitching slightly, firming beneath its fabric covering; maybe you’re not the only one thinking lewd thoughts.

You stare back up at Erwin, realising that you’ve not heard the sound of screwing for a while. His eyes are focused firmly on your chest, but his gaze soon shifts when he realises you’re watching.

Erwin clears his throat. ‘It’s all ready for you. We’ll start with fifteen, but if I don’t think you’ve worked hard enough, I’ll make you do more.’ Only fifteen? So much for breaking you.

You scoff. ‘That’s nothing. Besides, I’d like to see you make me do more. I’m the one in control here.’ It is ultimately your workout, after all…

Erwin chuckles, though it sounds darker than usual. ‘It’s sweet that you feel that way, but I am the one in control. You agreed to let me train you, so we’re going to do things my way. Now give me twenty lifts, or I’ll make you.’ Your inner masochist loves it when he treats you like this, so different from the cool head always seen by the rest of the world. 

You huff. ‘How about I give you thirty to prove I’m not a pushover?’ You don’t wait for him to give you an answer before you make a start, steadily raising and lowering the weight.

Erwin watches carefully, checking for any signs of you faltering. His now slightly stiffened crotch is still practically pushing itself against your face, the temptation to nudge it still very much in your mind. Touching it would be a bad idea though, especially while you’re lifting. If only there was a way…

You have to try to contain your smirk as you start counting out your lifts as less of a grunt, and more a moan, hoping the sound will effect Erwin.

It only takes you moaning out three numbers for Erwin to stiffen completely, his erection now pressed against your head as his mouth suddenly springs to life. ‘That’s it. Keep going like that. You’re doing so good for me. I can almost see your body getting stronger. You’re going to be so sore, but it’ll be worth it. Your body is going to get so firm, even more sexy. Those squats are going to make your ass so perfect. Like a juicy apple, begging me to take a bite.’ You have to put the weight down when you realise Erwin is more focused on rubbing himself against your face than he is making sure the weight doesn’t fall.

You sit up, and Erwin seems to snap back to his senses, guilt in his eyes. You’re certain he’s about to apologise, but you stop him dead in his tracks when you peel your vest from your body, flinging it across the room carelessly.

You look back at Erwin, biting your lip. ‘I’m getting so hot from my work out. What should I do next, trainer? We’ve already worked on my arms and my thighs, so I think we should focus on a new area. My throat could do with a good stretch, I think. I’m sure my breasts could do with a workout too. Or would you prefer to work on my core muscles? That’s probably the area that’ll leave me the sorest, and you did so desperately want to leave me sore, right?’ You have to admit though, the kind of soreness you’re thinking of is a million times better than any kind of workout.

Erwin takes the hint immediately, rushing over you to weave his fingers through your hair, pulling tightly. ‘So, you’re admitting I’m the one in charge of your workout then?’ Fuck, his grip is so strong. The raw power in his grasp is almost overpowering, your whole body telling you to surrender to the incredibly handsome man so he can give you exactly what you’re craving; the oldest workout in nature.

Your mouth has over ideas. ‘I was just asking your opinion. I’m rather craving a core workout now that I think about it. I could always plank for a while. That usually give me the sweet burn I’m after.’ It would also give Erwin a good view of the ass he craves so much, the best kind of bonus.

His eyes trailing up your spine, Erwin shakes his head. ‘I’ve got something a little better in mind, but for now, I have to take care of a distraction.’ Using his grip on your hair, he pushes you flat against the bench, the structure groaning in protest. 

Speaking of groaning, Erwin finally releases your hair, his hands easily undoing the clasp of your bra. You’re expecting his hands to side under you and grab your breasts, so you’re surprised when they grasp your hips firm enough to leave bruises.

You’re even more surprised when you feel something wet slide along the length of your spine.

The moan you let out makes you sound like a whore, but you don’t care; you could faint with the pleasure, all caused by such a simple act.

Erwin’s still-clothed body is pressed firmly into you as he whispers in your ear, erection digging into your ass desperately. ‘Such a beautiful noise. If you admit that I’m in charge, you’ll make even more. You’re always so good to me, my loyal friend. Yet when I see you, I get this urge to just bury myself inside you until you scream for me.’ He shifts slightly to bite down hard on your shoulder, a surprised cry of pleasure slipping past your lips. ‘See? You’re so wonderful, such a beautiful woman. I’ve never heard sweeter cries.’ Your body is burning up now, his words of praise almost too much. Fuck, you need this so bad…

You rub your ass against him as best you can, trying not to sob with want. ‘You’re in charge. You’ve always been in charge. Please, demonstrate the best way to work my core.’ To your disappointment, Erwin stands, but that disappointment doesn’t last when you realise he’s stripping off his clothes.

Eager, you stand and do the same, your underwear sticking slightly as you work it down your body.

Finally nude, Erwin sits with his legs out, prominent erection on full display. ‘Come here.’ You don’t need to be told twice; you’re straddling his lap before you even know what you’re doing, deliberately rubbing your clit against him as you get comfortable.

Erwin bites your neck this time, and you dig your nails in his arms to keep from falling. ‘I love seeing you so willing and eager. You look so sexy wearing nothing but sweat and bite marks.’ He bites you just above your breast, and you bring one hand up grasp his short strands, the other now digging into his back.

Erwin groans, the sound someone making you wetter. ‘That’s it, use your claws my feisty little minx. I want to have marks that last for days.’ So do you. You want evidence of Erwin all over your body, bites and bruises alike.

Speaking of bruises, Erwin grips your hips even tighter than before as he lines you up with his erection, the tip already sliding into you with no effort on your part.

As you slowly sink down on Erwin, you find the stretch of his impressive girth inside you aches more than the squats did; you could get addicted to this sweet, sweet stretch.

Erwin holds you still for a moment, trying to help you adjust. You’re having none of that; you buck your hips wildly until his grip relents, and you can ride him enthusiastically.

Everything becomes such a blur as you lose yourself to pleasure. All you’re aware of is the feeling of Erwin’s strong torso underneath your nails, your clawing and scratching so uncontrolled you know you must have made him draw blood. 

Then Erwin yanks your hair back to bite your neck, and you swear you can see stars. 

You don’t know how you focus enough to keep moving on top of Erwin, especially when one large thumb begins to rub your clit in circles, your body squeezing Erwin even tighter as a result.

You can’t take much more of that. You can feel your orgasm building inside of you, a dam of pleasure about to burst.

Erwin somehow manages to start grunting words into your ear. ‘You’ve earned this. You’re such a good girl. I need to feel you fall apart so I can follow. Can you do that for me, beautiful?’ As if you could ever ignore a director order from Captain Handsome himself!

A few more of Erwin’s powerful thrusts sends you over the edge, stars bursting from behind your eyes as you almost collapse from ecstasy.

Erwin can’t contain his own pleasure ether; he finishes moments later, spilling himself inside you as he desperately bucks up into you, milking out every last moment of his orgasm.

As you sit panting on Erwin’s lap, trying to collect your thoughts, one of his hands starts to stroke your hair softly, his voice warm and low. ‘You did well today. I didn’t think you had it in you to last a training session with me. I think I underestimated you.’ Damn right he did…

You smirk at him, mind still hazy. ‘You mean we’re finished here? I thought you were going to drill me harder than this.’ You love pushing your luck today, especially with Erwin.

Erwin simply leans forward, placing a single brief kiss on your lips. ‘You asked for it.’ With that, he pushes you to the floor, his body readying itself to drill you all over again. 

This is the best workout you’ve ever had.


End file.
